The present invention relates generally to a compressor system. More particularly, the present invention relates to an air/oil separator tank for use with an air compressor.
In conventional air compressor systems air is compressed in a compression chamber or airend of a compressor, for example, by a set of rotary screws, and a lubricant, such as oil, is injected into the compression chamber and mixes with the compressed air. The oil is generally injected into the compression chamber for a number of reasons including cooling the air compressor system, lubricating bearings, balancing axial forces and sealing the rotary screws. Although using oil is essential for operating these types of air compressor systems, the oil must be removed from the stream of compressed air before the compressed air may be used downstream for pneumatic equipment and/or other tools.
In such conventional air compressor systems, the compressed air and oil mixture discharged from the airend of the compressor flows with a high velocity into a separator tank where the air and oil of the air/oil mixture are caused to separate. The separator tank is usually cylindrical and the air/oil mixture is directed around an inner wall of a separation chamber. The combination of the centrifugal forces acting on the air/oil mixture and contact between the air/oil mixture and the inner wall of the separation chamber causes much of the oil to separate from the air/oil mixture, thereby allowing gravity to draw most of the oil downwardly into a lower portion of the separation chamber and also allowing the air to separate from the oil and flow upwardly into an upper portion of the separation chamber to achieve primary separation.
In these conventional air compressor systems, the compressed air, along with some fine oil droplets or mist entrained therein, passes through a separator element placed within the upper portion of the separation chamber, thereby coalescing most of the remaining oil in the air stream to achieve secondary separation before the compressed air is transferred out of the separator tank. The coalesced oil pools in a bottom portion of the separator element and is returned to the airend of the compressor by a scavenging line.
Conventional air compressor systems as described above typically include a lid mounted on the separator tank to hold the separator element within the separation chamber of the separator tank. The separator element must be held in place because there is an upward force on the separator element due to the pressure differential between the wet side (outer) and dry side (inner) portions of the separator element. Conventional air compressor systems include an air exit port in the lid, and typically, a minimum pressure check valve (MPCV) assembly is operatively connected to the air exit port in the lid. After passing through the MPCV assembly, the compressed air is typically sent to an aftercooler, and then the cooled compressed air may be conveyed to pneumatic equipment and/or other tools. As can be appreciated by those skilled in the art, it is generally necessary to service or replace separator elements from time-to-time. In the conventional air compressor systems described above, before a separator element can be serviced or replaced, the air discharge hose and MPCV assembly, which usually includes associated fittings, must be disconnected from the lid. This increases the time required to service or replace the separator element. Thus, there is a need for an air compressor system which eliminates the necessity of disconnecting the air discharge hose and MPCV assembly from the separator tank prior to servicing or replacing a separator element.
The conventional way to remove oil from inside a separator element of the air compressor systems described above is to pass an independent scavenge tube through the lid mounted on the tank and down into an open area of the separator element. The scavenge tube extends to the bottom of the separator element and draws off the excess oil to prevent saturation of the separating media of the separator element. Positioning the scavenge tube through the lid and down into the open area of the separator element can be problematic. If the scavenge tube is too long, it may puncture the bottom of the separator element. If the scavenge tube is too short, it may not be sufficiently effective in removing the oil. In addition, before the separator element is replaced, the scavenge tube must be removed from the separator tank lid. Thus, there is a need for a scavenging device which is easy to install, which does not adversely affect the servicing or replacing of a separator element, and which also effectively removes oil from the bottom of the separator element.
The present invention provides in one aspect thereof, a separator tank having an air exit port in a side wall of the tank, rather than in the lid of the tank as is the case with many known designs. Air from an air/oil mixture flows into an upper portion of a separation chamber of the tank, through a separator element positioned within the upper portion of the separation chamber, and out the air exit port in the side wall of the tank. An MPCV assembly is operatively connected to the air exit port in the side wall of the tank. Because the MPCV assembly and air discharge hose are not attached to the lid of the separator tank, in order to service or replace the separator element, the lid mounted on the separator tank is simply removed or pivoted out of the way to allow access to the separator element, without having to first disconnect the discharge hose and MPCV assembly.
The present invention provides in another aspect thereof, a separator element hold down mechanism between the separator element and the lid to position the separator element within the separation chamber and in spaced relation from the lid. Air separated from the air/oil mixture will flow through the separator element, towards the lid, and out the air exit port in the side wall of the separator tank.
The present invention provides in another aspect thereof, a separator element oil scavenge device which draws oil up off of the bottom of the separator element, and which transports the scavenged oil through the side wall of a separator tank. In one embodiment of the present invention, the scavenge device includes a tube which is integrally formed with the separator element. Once the tube is securely attached to the separator element and an end of the tube is located at a predetermined position relative to the bottom of the separator element, there is no need for independent adjustment of the tube relative to the bottom of the separator element and, as a consequence, no risk of making the tube too long or too short.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features.